Although Hopper is today one of the most beloved of American realists, he was slow to achieve success. He had his first solo exhibition in 1920, at the age of 37; nothing sold and there was little critical attention. But by 1930 his paintings had started to enter museum collections, and in 1933 the Museum of Modern Art, New York, mounted the first retrospective of his work. Office at Night (1940), one of Hopper’s best-known paintings, was inspired by a scene the artist glimpsed through an office window during a ride on one of New York’s elevated trains. In 1948, Hopper wrote to a Walker curator to explain that his aim with the painting was to evoke a lonely office interior high in the air. He declined to be specific about what was happening there, preferring to let viewers construct their own narratives.
[https://walkerart.org/collections/artists/edward-hopper]